Dual-shield question

catfishblues

catfishblues

Well-Known Member
Joined
Jul 26, 2005
Location
Pfafftown, NC
I've been running .045 dual-shield in my MM210 with 75-25 gas for a while now on a press we build. I'm really happy with the penetration and profile of the bead. I think we have it dialed-in about as right as we can. I'm running between 15 and 22 cfh of gas. The slag chips pretty easy. It doesn't peel off on its own like I'd like, but I'm also not having to pick it out with needles. The problem I'm having is porosity. It's not uncommon to find little wormhole looking tracks on the surface of the bead, and occasionally spongy porosity. The metal is clean, stickout is about 3/4", torch angle of 10-15° dragging the torch. What am I missing? I've got a few crappy cell pics if that would help.
 
It sounds like your shielding gas is not doing its job. Could be low volume, drafty work area, too much stickout, etc. I would try bumping up your volume of gas. I never run less than 25 cfh with C25. Also try bringing in your torch a little closer and make sure the area is not drafty/windy.

Also make sure what gas is appropriate for that dual-shield wire. Different wires tolerate different gasses.
 
Theoretically, straight CO2 would be the appropriate gas. My supplier, though, (who was a welder for years before getting into sales,) said it should be fine with unimix. Maybe he's wrong. I've tried running the CFH up to around 30, then back down. Seemed to work better at lower settings. I can't run any less stickout, it's already trying to burn back into the tip. And no, no drafts. Anybody else have experience with this stuff? @Mac5005 , @WARRIORWELDING ?
 
Stick out is recomended btween 1/2 and 3/4. Each manufacturer is fairly specific on the gas type. I have read several manufactures sudgest specific sheild gas. 25 cfm should be fine. I think the real problem might be available weld out put. These wires are designed for high deposition and travel speed. If its burning back on the tip alot you def. need more wire speed. Also check correct polarity, inner shield and flux core are different. Also try preheat, these wires are much like low hydrogen 7018 rods and should be stored and treated as such. Could be as simple as to much hydrogen present and insufficient puddle flow time to fully cook it out. These wires honestly don't like moderate speeds and setting, they are meant to roll out.
 
Truth on almost all the help, 25 cfm should be fine, I wouldn't go below that. I push my beads and it comes out like perfect flow. Smooth and flux peels off like scales. I do get those pesky worm lines every now and then, but not always. Sometimes with new wire I smell an ammonia smell while welding with it, but only the first day, after that, I don't smell it anymore. 210 is a bit small for. .045 I think. I used it with a 251 for a while, now I have a 3 phase unit and I have never turned it all the way up. But the tunability is crazy tight so it works really nicely...

Getting to my point of writing this, I think you might be getting some sort of contamination...my shielding cup has a fiberglass ring on the inside, sometimes over time they wear out and the fiber comes out with then gas and I start to get porous welds...just a thought.
 
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